In trying to better understand and evaluate potential contradictions in Islam, it is helpful to define both the word, "contradiction," and the word, "abrogation."An abrogation is "an act of repealing, superseding, putting aside (by formal means), or abolishing" while a contradiction is "a statement or proposition that contradicts or denies another or itself and is logically incongruous." That Allah would change his mind and abrogate a verse in the Quran is mentioned in the Quran: "Whatever communications We abrogate or cause to be forgotten, We bring one better than it or like it. Do you not know that Allah has power over all things?" (Quran 2:106, see also Quran 16:101). An example of abrogation is the following; Consider these two verses, which indicate the food of each inhabitant in Islamic hell:"No food will there be for them but a bitter Dhari [a thorny plant]" (Quran 88:6)"Nor has he any food except the foul discharge [or pus] from the washing of wounds" (Quran 69:36)Now as a thorny plant is not the same as discharge from a wound, we have a contradiction. The verses refer to what Allah intends to feed the inhabitants of hell in the future after the Day of Judgment, and Allah has changed his mind about what He wants to do. So we should determine which of the 2 verses abrogates the other. In this case, after doing a bit of research, we find that the later verse is 69:36 (The chapters of the Quran are not in chronological order). Thus, the residents of hell will eat only the discharge (or pus according to some translations) of wounds.Much more noteworthy and serious is what arises when 2 verses contradict each other, with neither (seemingly) abrogating the other. This suggests a mistake has been made.Consider the following: Muhammad proudly declared that he was the first Muslim (Quran 6:163, 39:11-12). But then on other occasions when reciting different Quranic verses, Muhammad stated that others were Muslims before him!! For example, "Ibrahim [someone alive long before Muhammad] was not a Jew nor a Christian but he was (an) upright (man), a Muslim, and he was not one of the polytheists." (Quran 3:67). In addition, we read that Jesus Christ's followers (living centuries before Muhammad) were Muslims (Quran 5:111): "...I inspired the disciples to have faith in Me and Mine Messenger: they said, 'We have faith, and do thou bear witness that we bow to Allah as Muslims.’"Our Debate Question: Can a truly omnipotent god of the universe allow anyone to enter mistakes into his divine book of revelation?